Light emitting panel assemblies

ABSTRACT

Light emitting panel assemblies include one or more light emitting panel members each having at least one pattern of optical deformities that may be varied in size, shape, density, placement, angle, rotation and/or type to obtain at least one light output distribution having a form or shape of at least one of text, graphics, logo or image. At least some of the optical deformities may be shaped or oriented preferentially to cause different colored light propagating through the panel member in different directions to create a multi-colored light output distribution. Also, a plurality of panel members each having a different light output distribution may be placed in overlying relation to one another to produce a composite output distribution when viewed through the panel members or a display overlying the panel members.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 09/256,275, filed Feb. 23, 1999 now U.S. Pat. No. 6,712,481,which is a continuation-in-part of U.S. patent application Ser. No.08/778,089, filed Jan. 2, 1997, now U.S. Pat. No. 6,079,838, dated Jun.27, 2000, which is a division of U.S. patent application Ser. No.08/495,176, filed Jun. 27, 1995, now U.S. Pat. No. 5,613,751, dated Mar.25, 1997.

BACKGROUND OF THE INVENTION

This invention relates generally, as indicated, to light emitting panelassemblies.

Light emitting panel assemblies are generally known. However, thepresent invention relates to several different light emitting panelassembly configurations which provide for better control of the lightoutput from the panel assemblies and more efficient utilization of lightto suit a particular application.

SUMMARY OF THE INVENTION

In accordance with one aspect of the invention, the light emitting panelassemblies include a light emitting panel member having a pattern ofindividual light extracting deformities of well defined shapes on or inone or more surface areas of the light emitting panel member.

In accordance with another aspect of the invention, the pattern ofoptical deformities may be varied in size, shape, density, placement,angle, rotation and/or type to obtain a desired light outputdistribution from the panel member to suit a particular application.

In accordance with another aspect of the invention, the pattern ofoptical deformities may be varied to obtain at least one light outputdistribution having a form or shape of at least one of text, graphics,logo or image.

In accordance with another aspect of the invention, the at least onelight output distribution may be located in another light outputdistribution of the panel member to create a watermark or other effectin the another output distribution.

In accordance with another aspect of the invention, the opticaldeformities may be varied to obtain at least one multi-intensity lightoutput distribution from the panel member to suit a particularapplication.

In accordance with another aspect of the invention, at least some of theoptical deformities may be shaped or oriented preferentially to extractlight propagating through the panel member in different directions.

In accordance with another aspect of the invention, at least some of theoptical deformities may be shaped or oriented preferentially to causedifferent colored light propagating through the panel member indifferent directions to create at least one multi-colored light outputdistribution.

In accordance with another aspect of the invention, a plurality of panelmembers each having at least one different light output distribution maybe disposed in overlying relation to one another to produce a compositelight output distribution when viewed through the panel members or adisplay overlying the panel members.

In accordance with another aspect of the invention, the intensity of atleast one light output distribution of each of the overlying panelmembers may be different to create a multi-intensity composite outputdistribution when viewed through the panel members.

In accordance with another aspect of the invention, at least one lightredirecting film may be positioned over one or more overlying panelmembers to allow different light output distributions to be seen whenthe panel members are viewed through the film or a display overlying thefilm from different angles.

In accordance with another aspect of the invention, the pattern ofoptical deformities may be on or in one side of the panel member andadditional optical deformities may be on or in the other side of thepanel member to allow different output distributions to be seen when thepanel member is viewed through the additional optical deformities in theother side.

These and other objects, advantages, features and aspects of theinvention will become apparent as the following description proceeds.

To the accomplishment of the foregoing and related ends, the inventionthen comprises the features hereinafter fully described and particularlypointed out in the claims, the following description and the annexeddrawings setting forth in detail certain illustrative embodiments of theinvention, these being indicative, however, of but several of thevarious ways in which the principles of the invention may be employed.

BRIEF DESCRIPTION OF THE DRAWINGS

In the annexed drawings:

FIGS. 1 through 3 are schematic perspective views of three differentforms of light emitting panel assemblies in accordance with thisinvention;

FIG. 4 a is an enlarged plan view of a portion of a light output area ofa panel assembly showing one form of pattern of light extractingdeformities on the light output area;

FIGS. 4 b, c and d are enlarged schematic perspective views of a portionof a light output area of a panel assembly showing other forms of lightextracting deformities formed in or on the light output area;

FIG. 5 is an enlarged transverse section through the light emittingpanel assembly of FIG. 3 taken generally on the plane of the line 5—5thereof;

FIG. 6 is a schematic perspective view of another form of light emittingpanel assembly in accordance with this invention;

FIG. 7 is a schematic top plan view of another form of light emittingpanel assembly in accordance with this invention;

FIG. 8 is a schematic perspective view of another form of light emittingpanel assembly in accordance with this invention;

FIG. 9 is a schematic top plan view of another form of light emittingpanel assembly in accordance with this invention;

FIG. 10 is a schematic top plan view of still another form of lightemitting panel assembly in accordance with this invention;

FIG. 11 is a side elevation view of the light emitting panel assembly ofFIG. 10;

FIG. 11 a is a fragmentary side elevation view showing a tapered orrounded end on the panel member in place of the prismatic surface shownin FIGS. 10 and 11;

FIG. 12 is a schematic top plan view of another form of light emittingpanel assembly in accordance with this invention;

FIG. 13 is a schematic side elevation view of the light emitting panelassembly of FIG. 12;

FIGS. 14 and 15 are schematic perspective views of still other forms oflight emitting panel assemblies in accordance with this invention;

FIGS. 16 and 17 are enlarged schematic fragmentary plan views of asurface area of a light panel assembly showing still other forms oflight extracting deformities in accordance with this invention formed onor in a surface of the panel member;

FIGS. 18 and 19 are enlarged longitudinal sections through one of thelight extracting deformities of FIGS. 16 and 17, respectively;

FIGS. 20 and 21 are enlarged schematic longitudinal sections throughlight extracting deformities similar to FIGS. 18 and 19, respectively,except that the deformity end walls are shown extending substantiallyperpendicular to the panel surface instead of perpendicular to theirrespective reflective/refractive surfaces as shown in FIGS. 18 and 19;

FIGS. 22 through 30 are enlarged schematic perspective views of panelsurface areas containing various patterns of individual light extractingdeformities of other well defined shapes in accordance with thisinvention;

FIG. 31 is an enlarged schematic longitudinal section through anotherform of light extracting deformity in accordance with this invention;

FIGS. 32 and 33 are enlarged schematic top plan views of panel surfaceareas containing light extracting deformities similar in shape to thoseshown in FIGS. 28 and 29 arranged in a plurality of straight rows alongthe length and width of the panel surface area;

FIGS. 34 and 35 are enlarged schematic top plan views of panel surfaceareas containing light extracting deformities also similar in shape tothose shown in FIGS. 28 and 29 arranged in staggered rows along thelength of the panel surface areas;

FIGS. 36 and 37 are enlarged schematic top plan views of panel surfaceareas containing a random or variable pattern of different sized lightemitting deformities on the panel surface areas;

FIG. 38 is an enlarged schematic perspective view of a panel surfacearea showing light extracting deformities in accordance with thisinvention increasing in size as the distance of the deformities from thelight source increases or intensity of the light increases along thelength of the panel surface area;

FIGS. 39 and 40 are schematic perspective views showing differentangular orientations of the light extracting deformities along thelength and width of a panel surface area;

FIGS. 41 and 42 are enlarged perspective views schematically showing howexemplary light rays emitted from a focused light source are reflectedor refracted by different individual light extracting deformities ofwell defined shapes in accordance with this invention;

FIG. 43 is a schematic perspective view showing a light emitting panelassembly similar to FIG. 42 placed on a front face of a display toprovide front lighting for the display;

FIG. 44 is a schematic top plan view of another form of light emittingpanel assembly in accordance with this invention for use in phototherapytreatment and the like;

FIGS. 45 through 47 are schematic side elevation views of still otherforms of light emitting panel assemblies in accordance with thisinvention for use in phototherapy treatment and the like;

FIGS. 48 and 49 are schematic perspective views of other forms of lightemitting panel assemblies in accordance with this invention having lightoutput distributions in the form or shape of text, graphics, logo and/orimage produced by variable patterns of individual optical deformities onor in the panel members;

FIG. 50 is a schematic perspective view of another form of lightemitting panel assembly including at least one light output distributionin the form or shape of text, graphics, logo and/or image located inanother light output distribution to create a “watermark” or othereffect;

FIG. 51 is a schematic perspective view of an optical assembly inaccordance with this invention including a screen display that isbacklighted for example by the light emitting panel assembly of FIG. 50with the text, graphics, logo and/or image output distribution of thebacklight visible for example in a corner of the display; and

FIG. 52 is an exploded perspective view of another form of opticalassembly in accordance with this invention including two or more lightemitting panel assemblies in overlying relation to one another eachhaving different light output distributions that produce one or moreparts of a more complex output distribution in the form or shape oftext, graphics, logo and/or image that is visible through the panelmembers and/or an optical film and/or a display overlying the panelmembers when viewed therethrough.

DETAILED DESCRIPTION OF THE INVENTION

Referring now in detail to the drawings, and initially to FIG. 1, thereis schematically shown one form of light emitting panel assembly 1 inaccordance with this invention including a transparent light emittingpanel 2 and one or more light sources 3 which emit light in apredetermined pattern in a light transition member or area 4 used tomake the transition from the light source 3 to the light emitting panel2, as well known in the art. The light that is transmitted by the lighttransition area 4 to the transparent light emitting panel 2 may beemitted along the entire length of the panel or from one or more lightoutput areas along the length of the panel as desired to produce adesired light output distribution to fit a particular application.

In FIG. 1 the light transition area 4 is shown as an integral extensionof one end of the light emitting panel 2 and as being generallyrectangular in shape. However, the light transition area may be of othershapes suitable for embedding, potting, bonding or otherwise mountingthe light source. Also, reflective or refractive surfaces may beprovided to increase efficiency. Moreover, the light transition area 4may be a separate piece suitably attached to the light input surface 13of the panel member if desired. Also, the sides of the light transitionarea may be curved to more efficiently reflect or refract a portion ofthe light emitted from the light source through the light emitting panelat an acceptable angle.

FIG. 2 shows another form of light emitting panel assembly 5 inaccordance with this invention including a panel light transition area 6at one end of the light emitting panel 7 with sides 8, 9 around andbehind the light source 3 shaped to more efficiently reflect and/orrefract and focus the light emitted from the light source 3 thatimpinges on these surfaces back through the light transition area 6 atan acceptable angle for entering the light input surface 18 at one endof the light emitting panel 7. Also, a suitable reflective material orcoating 10 may be provided on the portions of the sides of the lighttransition areas of the panel assemblies of FIGS. 1 and 2 on which aportion of the light impinges for maximizing the amount of light orotherwise changing the light that is reflected back through the lighttransition areas and into the light emitting panels.

The panel assemblies shown in FIGS. 1 and 2 include a single lightsource 3, whereas FIG. 3 shows another light emitting panel assembly 11in accordance with this invention including two light sources 3. Ofcourse, it will be appreciated that the panel assemblies of the presentinvention may be provided with any number of light sources as desired,depending on the particular application.

The panel assembly 11 of FIG. 3 includes a light transition area 12 atone end of the light emitting panel 14 having reflective and/orrefractive surfaces 15 around and behind each light source 3. Thesesurfaces 15 may be appropriately shaped including for example curved,straight and/or faceted surfaces, and if desired, suitable reflectivematerials or coatings may be provided on portions of these surfaces tomore efficiently reflect and/or refract and focus a portion of the lightemitted for example from an incandescent light source which emits lightin a 360° pattern through the light transition areas 12 into the lightinput surface 19 of the light emitting panel 14.

The light sources 3 may be mechanically held in any suitable manner inslots, cavities or openings 16 machined, molded or otherwise formed inthe light transition areas of the panel assemblies. However, preferablythe light sources 3 are embedded, potted or bonded in the lighttransition areas in order to eliminate any air gaps or air interfacesurfaces between the light sources and surrounding light transitionareas, thereby reducing light loss and increasing the light outputemitted by the light emitting panels. Such mounting of the light sourcesmay be accomplished, for example, by bonding the light sources 3 in theslots, cavities or openings 16 in the light transition areas using asufficient quantity of a suitable embedding, potting or bonding material17. The slots, cavities or openings 16 may be on the top, bottom, sidesor back of the light transition areas. Bonding can also be accomplishedby a variety of methods that do not incorporate extra material, forexample, thermal bonding, heat staking, ultrasonic or plastic welding orthe like. Other methods of bonding include insert molding and castingaround the light source(s).

A transparent light emitting material of any suitable type, for exampleacrylic or polycarbonate, may be used for the light emitting panels.Also, the panels may be substantially flat, or curved, may be a singlelayer or multi-layers, and may have different thicknesses and shapes.Moreover, the panels may be flexible, or rigid, and may be made out of avariety of compounds. Further, the panels may be hollow, filled withliquid, air, or be solid, and may have holes or ridges in the panels.

Each light source 3 may also be of any suitable type including, forexample, any of the types disclosed in U.S. Pat. Nos. 4,897,771 and5,005,108, assigned to the same assignee as the present application, theentire disclosures of which are incorporated herein by reference. Inparticular, the light sources 3 may be an arc lamp, an incandescent bulbwhich also may be colored, filtered or painted, a lens end bulb, a linelight, a halogen lamp, a light emitting diode (LED), a chip from an LED,a neon bulb, a fluorescent tube, a fiber optic light pipe transmittingfrom a remote source, a laser or laser diode, or any other suitablelight source. Additionally, the light sources 3 may be a multiplecolored LED, or a combination of multiple colored radiation sources inorder to provide a desired colored or white light output distribution.For example, a plurality of colored lights such as LEDs of differentcolors (red, blue, green) or a single LED with multiple colored chipsmay be flashed to create white light or any other desired colored lightoutput distribution by varying the intensities of each different coloredlight or different colored chip.

A pattern of light extracting deformities or disruptions may be providedon one or both sides of the panel members or on one or more selectedareas on one or both sides of the panel members, as desired. FIG. 4 aschematically shows one such light surface area 20 on which a pattern oflight extracting deformities or disruptions 21 is provided. As usedherein, the term deformities or disruptions are used interchangeably tomean any change in the shape or geometry of the panel surface and/orcoating or surface treatment that causes a portion of the light to beemitted. The pattern of light extracting deformities 21 shown in FIG. 4a includes a variable pattern which breaks up the light rays such thatthe internal angle of reflection of a portion of the light rays will begreat enough to cause the light rays either to be emitted out of thepanel through the side or sides on which the light extractingdeformities 21 are provided or reflected back through the panel andemitted out the other side.

These deformities or disruptions 21 can be produced in a variety ofmanners, for example, by providing a painted pattern, an etched pattern,a machined pattern, a printed pattern, a hot stamped pattern, or amolded pattern or the like on selected light output areas of the panelmembers. An ink or printed pattern may be applied for example by padprinting, silk screening, ink jet, heat transfer film process or thelike. The deformities may also be printed on a sheet or film which isused to apply the deformities to the panel member. This sheet or filmmay become a permanent part of the light panel assembly for example byattaching or otherwise positioning the sheet or film against one or bothsides of the panel member similar to the sheet or film 27 shown in FIGS.3 and 5 in order to produce a desired effect.

By varying the density, opaqueness or translucence, shape, depth, color,area, index of refraction, or type of deformities 21 on an area or areasof the panels, the light output of the panels can be controlled. Thedeformities or disruptions may be used to control the percent of lightemitted from any area of the panels. For example, less and/or smallersize deformities 21 may be placed on panel areas where less light outputis wanted. Conversely, a greater percentage of and/or larger deformitiesmay be placed on areas of the panels where greater light output isdesired.

Varying the percentages and/or size of deformities in different areas ofthe panel is necessary in order to provide a uniform light outputdistribution. For example, the amount of light traveling through thepanels will ordinarily be greater in areas closer to the light sourcethan in other areas further removed from the light source. A pattern oflight extracting deformities 21 may be used to adjust for the lightvariances within the panel members, for example, by providing a denserconcentration of light extracting deformities with increased distancefrom the light source 3 thereby resulting in a more uniform light outputdistribution from the light emitting panels.

The deformities 21 may also be used to control the output ray angledistribution of the emitted light to suit a particular application. Forexample, if the panel assemblies are used to provide a liquid crystaldisplay back light, the light output will be more efficient if thedeformities 21 cause the light rays to emit from the panels atpredetermined ray angles such that they will pass through the liquidcrystal display with low loss.

Additionally, the pattern of light extracting deformities may be used toadjust for light output variances attributed to light extractions of thepanel members. The pattern of light extracting deformities 21 may beprinted on the light output areas utilizing a wide spectrum of paints,inks, coatings, epoxies, or the like, ranging from glossy to opaque orboth, and may employ half-tone separation techniques to vary thedeformity 21 coverage. Moreover, the pattern of light extractingdeformities 21 may be multiple layers or vary in index of refraction.

Print patterns of light extracting deformities 21 may vary in shapessuch as dots, squares, diamonds, ellipses, stars, random shapes, and thelike, and are desirably 0.006 square inch per deformity/element or less.Also, print patterns that are 60 lines per inch or finer are desirablyemployed, thus making the deformities or shapes 21 in the print patternsnearly invisible to the human eye in a particular application therebyeliminating the detection of gradient or banding lines that are commonto light extracting patterns utilizing larger elements. Additionally,the deformities may vary in shape and/or size along the length and/orwidth of the panel members. Also, a random placement pattern of thedeformities may be utilized throughout the length and/or width of thepanel members. The deformities may have shapes or a pattern with nospecific angles to reduce moiré or other interference effects. Examplesof methods to create these random patterns are printing a pattern ofshapes using stochastic print pattern techniques, frequency modulatedhalf tone patterns, or random dot half tones. Moreover, the deformitiesmay be colored in order to effect color correction in the panel members.The color of the deformities may also vary throughout the panel members,for example to provide different colors for the same or different lightoutput areas.

In addition to or in lieu of the patterns of light extractingdeformities 21 shown in FIG. 4 a, other light extracting deformitiesincluding prismatic surfaces, depressions or raised surfaces of variousshapes using more complex shapes in a mold pattern may be molded,etched, stamped, thermoformed, hot stamped or the like into or on one ormore areas of the panel member. FIGS. 4 b and 4 c show panel areas 22 onwhich prismatic surfaces 23 or depressions 24 are formed in the panelareas, whereas FIG. 4 d shows prismatic or other reflective orrefractive surfaces 25 formed on the exterior of the panel area. Theprismatic surfaces, depressions or raised surfaces will cause a portionof the light rays contacted thereby to be emitted from the panel member.Also, the angles of the prisms, depressions or other surfaces may bevaried to direct the light in different directions to produce a desiredlight output distribution or effect. Moreover, the reflective orrefractive surfaces may have shapes or a pattern with no specific anglesto reduce moire or other interference effects.

As best seen in the cross sectional view of FIG. 5, a back reflector(including trans reflectors) 26 may be attached or positioned againstone side of the panel member 14 of FIG. 3 using a suitable adhesive 28or other method in order to improve light output efficiency of the panelassembly 11 by reflecting the light emitted from that side back throughthe panel for emission through the opposite side. Additionally, apattern of light extracting deformities 21, 23, 24 and/or 25 may beprovided on one or both sides of the panel member in order to change thepath of the light so that the internal critical angle is exceeded and aportion of the light is emitted from one or both sides of the panel.Moreover, a transparent film, sheet or plate 27 may be attached orpositioned against the side or sides of the panel member from whichlight is emitted using a suitable adhesive 28 or other method in orderto produce a desired effect.

The member 27 may be used to further improve the uniformity of the lightoutput distribution. For example, the member 27 may be a colored film, adiffuser, or a label or display, a portion of which may be a transparentoverlay that may be colored and/or have text or an image thereon.

If adhesive 28 is used to adhere the back reflector 26 and/or film 27 tothe panel, the adhesive is preferably applied only along the side edgesof the panel, and if desired the end edge opposite the light transitionareas 12, but not over the entire surface area or areas of the panelbecause of the difficulty in consistently applying a uniform coating ofadhesive to the panel. Also, the adhesive changes the internal criticalangle of the light in a less controllable manner than the air gaps 30(see FIG. 5) which are formed between the respective panel surfaces andthe back reflector 26 and/or film 27 when only adhered along theperipheral edges. Additionally, longer panel members are achievable whenair gaps 30 are used. If adhesive were to be used over the entiresurface, the pattern of deformities could be adjusted to account for theadditional attenuation in the light caused by the adhesive.

Referring further to FIG. 2, the panel assembly 5 shown therein alsoincludes molded posts 31 at one or more corners of the panel 7 (foursuch posts being shown) which may be used to facilitate mounting of thepanel assembly and providing structural support for other parts orcomponents, for example, a display panel such as a liquid crystaldisplay panel as desired.

FIG. 6 shows another form of light emitting panel assembly 32 inaccordance with this invention including a panel member 33, one or morelight sources 3, and one or more light output areas 34. In addition, thepanel assembly 32 includes a tray 35 having a cavity or recess 36 inwhich the panel assembly 32 is received. The tray 35 may act as a backreflector as well as end edge and/or side edge reflectors for the panel33 and side and/or back reflectors 37 for the light sources 3.Additionally, one or more secondary reflective or refractive surfaces 38may be provided on the panel member 33 and/or tray 35 to reflect aportion of the light around one or more corners or curves in anon-rectangular shaped panel member 33. These secondaryreflective/refractive surfaces 38 may be flat, angled, faceted orcurved, and may be used to extract a portion of the light away from thepanel member in a predetermined pattern. FIG. 6 also shows multiplelight output areas 34 on the panel member that emit light from one ormore light sources 3.

FIG. 7 is a schematic illustration of still another form of lightemitting panel assembly 40 in accordance with this invention including apanel member 41 having one or more light output areas 42 and one or morelight transition areas (mixing areas) 43 containing a plurality of lightsources 3 at one or both ends of the panel. Each transition area mixesthe light from one or more light sources having different colors and/orintensities. In this particular embodiment, each of the light sources 3desirably employs three colored LEDs (red, blue, green) in eachtransition mixing area 43 so that the light from the three LEDs can bemixed to produce a desired light output color that will be emitted fromthe light output area 42. Alternatively, each light source may be asingle LED having multiple colored chips bonded to the lead film. Also,two colored LEDs or a single LED having two colored chips may be usedfor a particular application. By varying the intensities of theindividual respective LEDs, virtually any colored light output or whitelight distribution can be achieved.

FIG. 8 shows yet another form of light emitting panel assembly 45 inaccordance with this invention including a light emitting panel member46 and a light source 3 in a light transition area 48 integral with oneend of the panel member. In this particular embodiment, the panel member46 is three-dimensionally curved, for example, such that light rays maybe emitted in a manner that facilitates aesthetic design of a lighteddisplay.

FIG. 9 schematically shows another form of light emitting panel assembly50 in accordance with this invention, including a panel member 51 havingmultiple light output areas 52, and mounting posts and/or mounting tabs53. This particular panel assembly 50 may serve as a structural memberto support other parts or components as by providing holes or cavities54, 55 in the panel member 51 which allow for the insertion of modularcomponents or other parts into the panel member. Moreover, a separatecavity or recess 56 may be provided in the panel member 51 for receiptof a correspondingly shaped light transition area 57 having one or morelight sources 3 embedded, bonded, cast, insert molded, epoxied, orotherwise mounted or positioned therein and a curved reflective orrefractive surface 58 on the transition area 57 and/or wall of thecavity or recess 56 to redirect a portion of the light in apredetermined manner. In this way the light transition area 57 and/orpanel member may be in the form of a separate insert which facilitatesthe easy placement of the light source in a modular manner. A reflector58 may be placed on the reflective or refractive surface of the cavityor recess 56 or insert 57. Where the reflector 58 is placed on thereflective or refractive surface of the cavity or recess 56, the cavityor recess may act as a mold permitting transparent material from whichthe transition area 57 is made to be cast around one or more lightsources 3.

FIGS. 10 and 11 schematically show another form of light emitting panelassembly 60 in accordance with this invention including a panel member61 having one or more light output areas 62. In this particularembodiment, an off-axis light transition area 63 is provided that isthicker in cross section than the panel member to permit use of one ormore light sources 3 embedded or otherwise mounted in the lighttransition area that are dimensionally thicker than the panel member.Also, a three-dimensional reflective surface 64 (FIG. 11) may beprovided on the transition area 63. Moreover, a prism 65 (FIG. 11) ortapered, rounded, or otherwise shaped end 66 (FIG. 11 a) may be providedat the end of the panel opposite the light sources 3 to perform thefunction of an end reflector. The light sources 3 may be oriented atdifferent angles relative to each other and offset to facilitate bettermixing of the light rays 67 in the transition area 63 as schematicallyshown in FIG. 10 and/or to permit a shorter length transition area 63 tobe used.

FIGS. 12 and 13 schematically show still another form of light emittingpanel assembly 70 in accordance with this invention which includes oneor more light transition areas 71 at one or both ends of the panelmember 72 each containing a single light source 73. The transition areaor areas 71 shown in FIGS. 12 and 13 collect light with multiple orthree-dimensional surfaces and/or collect light in more than one plane.For example each transition area 71 shown in FIGS. 12 and 13 haselliptical and parabolic shape surfaces 74 and 75 in different planesfor directing the light rays 76 into the panel member at a desiredangle.

Providing one or more transition areas at one or both ends of the panelmember of any desired dimension to accommodate one or more lightsources, with reflective and/or refractive surfaces on the transitionareas for redirecting the light rays into the panel member at relativelylow angles allows the light emitting panel member to be made much longerand thinner than would otherwise be possible. For example the panelmembers of the present invention may be made very thin, i.e., 0.125 inchthick or less.

FIG. 14 schematically illustrates still another form of light emittingpanel assembly 80 in accordance with this invention including a lightemitting panel 81 and one or more light sources 3 positioned, embedded,potted, bonded or otherwise mounted in a light transition area 82 thatis at an angle relative to the panel member 81 to permit more efficientuse of space. An angled or curved reflective or refractive surface 83 isprovided at the junction of the panel member 81 with the transition area82 in order to reflect/refract light from the light source 3 into thebody of the panel member 81 for emission of light from one or more lightemitting areas 84 along the length of the panel member.

FIG. 15 schematically illustrates still another form of light emittingpanel assembly 90 in accordance with this invention including a lighttransition area 91 at one or both ends of a light emitting panel member92 containing a slot 93 for sliding receipt of an LED or other suitablelight source 3. Preferably the slot 93 extends into the transition area91 from the back edge 94, whereby the light source 3 may be slid and/orsnapped in place in the slot from the back, thus allowing the transitionarea to be made shorter and/or thinner. The light source 3 may beprovided with wings, tabs or other surfaces 95 for engagement incorrespondingly shaped recesses or grooves 96 or the like in thetransition area 91 for locating and, if desired, securing the lightsource in place. Also, the light source 3 may be embedded, potted,bonded or otherwise secured within the slot 93 in the light transitionarea 91 of the panel member 92. Light from a secondary light source 97may be projected through the panel member 92 for indication or someother effect.

FIG. 16 through 19 show other light extracting deformities 98 inaccordance with this invention which may either be individualprojections 99 on the respective panel surface areas 22 or individualdepressions 100 in such panel surface areas. In either case, the lightextracting deformities 98 differ from the light extracting deformitiesshown in FIGS. 4 a, 4 b, 4 c and 4 d in that each of the deformities 98has a well defined shape including a reflective or refractive surface101 that intersects the respective panel surface area 22 at one edge 102and has a uniform slope throughout its length for more preciselycontrolling the emission of light by each of the deformities. Along aperipheral edge portion 103 of each reflective/refractive surface 101 isan end wall 104 of each deformity 98 that intersects the respectivepanel surface area at a greater included angle I than the included angleI′ between the reflective/refractive surfaces 101 and the panel surfacearea 22 (see FIGS. 18 and 19) to minimize the projected surface area ofthe end walls on the panel surface area. This allows more deformities 98to be placed on or in the panel surface areas than would otherwise bepossible if the projected surface areas of the end walls 104 weresubstantially the same as or greater than the projected surface areas ofthe reflective/refractive surfaces 101.

In FIGS. 16 and 17 the peripheral edge portions 103 of thereflective/refractive surfaces 101 and associated end walls 104 arecurved in the transverse direction. Also, in FIGS. 18 and 19 the endwalls 104 of the deformities 98 are shown extending substantiallyperpendicular to the reflective/refractive surfaces 101 of thedeformities. Alternatively, such end walls 104 may extend substantiallyperpendicular to the panel surface areas 22 as schematically shown inFIGS. 20 and 21. This virtually eliminates any projected surface area ofthe end walls 104 on the panel surface areas 22 whereby the density ofthe deformities on the panel surface areas may be even furtherincreased.

The light extracting deformities may also be of other well definedshapes to obtain a desired light output distribution from a panelsurface area. FIG. 22 shows individual light extracting deformities 105on a panel surface area 22 each including a generally planar,rectangular reflective/refractive surface 106 and associated end wall107 of a uniform slope throughout their length and width and generallyplanar side walls 108. Alternatively, the deformities 105′ may haverounded or curved side walls 109 as schematically shown in FIG. 23.

FIG. 24 shows individual light extracting deformities 110 on a panelsurface area 22 each including a planar, sloping triangular shapedreflective/refractive surface 111 and associated planar, generallytriangularly shaped side walls or end walls 112. FIG. 25 showsindividual light extracting deformities 115 each including a planarsloping reflective/ refractive surface 116 having angled peripheral edgeportions 117 and associated angled end and side walls 118 and 119.

FIG. 26 shows individual light extracting deformities 120 which aregenerally conically shaped, whereas FIG. 27 shows individual lightextracting deformities 121 each including a roundedreflective/refractive surface 122 and rounded end wall 123 and roundedor curved side walls 124 all blended together.

Regardless of the particular shape of the reflective/refractive surfacesand end and side walls of the individual deformities, such deformitiesmay also include planar surfaces intersecting the reflective/refractivesurfaces and end and/or side walls in parallel spaced relation to thepanel surface areas 22. FIGS. 28 through 30 show deformities 125, 126and 127 in the form of individual projections on a panel surface area 22having representative shapes similar to those shown in FIGS. 22, 23 and26, respectively, except that each deformity is intersected by a planarsurface 128 in parallel spaced relation to the panel surface area 22. Inlike manner, FIG. 31 shows one of a multitude of deformities 129 in theform of individual depressions 130 in a panel surface area 22 eachintersected by a planar surface 128 in parallel spaced relation to thegeneral planar surface of the panel surface area 22. Any light rays thatimpinge on such planar surfaces 128 at internal angles less than thecritical angle for emission of light from the panel surface area 22 willbe internally reflected by the planar surfaces 128, whereas any lightrays impinging on such planar surfaces 128 at internal angles greaterthan the critical angle will be emitted by the planar surfaces withminimal optical discontinuities as schematically shown in FIG. 31.

Where the deformities are projections on the panel surface area 22, thereflective/refractive surfaces extend at an angle away from the panel ina direction generally opposite to that in which the light rays from thelight source 3 travel through the panel as schematically shown in FIGS.18 and 20. Where the deformities are depressions in the panel surfacearea, the reflective/refractive surfaces extend at an angle into thepanel in the same general direction in which the light rays from thelight source 3 travel through the panel member as schematically shown inFIGS. 19 and 21.

Regardless of whether the deformities are projections or depressions onor in the panel surface areas 22, the slopes of the lightreflecting/refractive surfaces of the deformities may be varied to causethe light rays impinging thereon to be either refracted out of the lightemitting panel or reflected back through the panel and emitted out theopposite side of the panel which may be etched to diffuse the lightemitted therefrom or covered by a transparent film, sheet or platesimilar to the film 27 shown in FIGS. 3 and 5 to produce a desiredeffect.

Also, the pattern of light extracting deformities on the panel surfaceareas may be uniform or variable as desired to obtain a desired lightoutput distribution from the panel surface areas. FIGS. 32 and 33 showdeformities 125 and 126 similar in shape to those shown in FIGS. 28 and29 arranged in a plurality of generally straight uniformly spaced apartrows along the length and width of a panel surface area 22, whereasFIGS. 34 and 35 show such deformities 125 and 126 arranged in staggeredrows along the length of a panel surface area.

Also, the size, including the width, length and depth or height as wellas the angular orientation and position or location of the lightextracting deformities may vary along the length and/or width of anygiven panel surface area to obtain a desired light output distributionfrom the panel surface area. FIGS. 36 and 37 show a random or variablepattern of different sized deformities 105 and 105′ similar in shape tothose shown in FIGS. 22 and 23, respectively, arranged in staggered rowson a panel surface area 22, whereas FIG. 38 shows deformities 126similar in shape to those shown in FIG. 29 increasing in size as thedistance of the deformities from the light source increases or intensityof the light decreases along the length and/or width of the panelsurface area 22.

FIGS. 39 and 40 schematically show different angular orientations oflight extracting deformities 135 of any desired shape along the lengthand width of a panel surface area 22. In FIG. 39 the light extractingdeformities 135 are arranged in straight rows 136 along the length ofthe panel surface area but the deformities in each of the rows areoriented to face the light source 3 so that all of the deformities aresubstantially in line with the light rays being emitted from the lightsource. In FIG. 40 the deformities 135 are also oriented to face thelight source 3 similar to FIG. 39. In addition, the rows 137 ofdeformities in FIG. 40 are in substantial radial alignment with thelight source.

FIGS. 41 and 42 schematically show how exemplary light rays 140 emittedfrom a focused light source 3 insert molded or cast within a lighttransition area 6 of a light emitting panel assembly 5 in accordancewith this invention are reflected during their travel through the lightemitting panel member 7 until they impinge upon individual lightextracting deformities 98, 126 of well defined shapes on or in a panelsurface area 22 causing more of the light rays to be reflected orrefracted out of one side 141 of the panel member than the other side142. In FIG. 41 the exemplary light rays 140 are shown being reflectedby the reflective/refractive surfaces 101 of the deformities 98 in thesame general direction out through the same side 141 of the panelmember, whereas in FIG. 42 the light rays 140 are shown being scatteredin different directions within the panel member 7 by the rounded sidewalls 109 of the deformities 126 before the light rays arereflected/refracted out of the same side 141 of the panel member. Such apattern of individual light extracting deformities of well definedshapes in accordance with the present invention can cause 60 to 70% ormore of the light received through the input edge 18 of the panel memberto be emitted from the same side of the panel member.

FIG. 43 schematically shows the side 141 of the light emitting panelassembly 5 of FIG. 42 from which a majority of the light is emittedplaced against the front face 143 of a liquid crystal display or othersignage 144 for front lighting the display/signage when the ambientlight is not sufficient for proper illumination. The portions of thepanel member 7 overlying the display/signage 144 are transparent withoutany back reflector, whereby when the light source 3 is energized, lightwill be emitted from the side 141 of the panel member 7 contacting thefront face 143 of the display/signage 144 and then reflected back outthrough the panel member 7 including particularly the planar surfaces128 on the deformities.

By selecting the optical index of refraction of the panel member 7 toclosely match the substrate of the display/signage 144, the lightreflected by the display/signage will pass through the planar surfaces128 of the deformities with minimal optical discontinuities for ease ofviewing the display/signage. Also, providing a random or variablepattern of light extracting deformities on the panel member insures thatthe spacing of the light extracting deformities does not match the pixelspacing of the display so as not to produce a headlight effect.

Because the light extracting deformities are of well defined shapes, thesize, shape, location and orientation of each light extracting deformitycan be individually adjusted or randomly varied at any given surfacearea of the panel member to spread the light output distributionuniformly across each panel surface area or obtain any other desiredlight output distribution at each panel surface area. Also, such lightextracting deformities may be formed in or on any surface area of thepanel member in any desired manner, such as by machining using a millingor laser cutter, or by molding or stamping or the like.

The light source 3 for the panel assemblies shown in FIGS. 16, 17 and 39through 43 may be of any suitable type as previously described. However,preferably such light source is a focused light source such as a lensend bulb, a chip from an LED, or a laser or laser diode. Alternativelysuch light source may be an LED, incandescent lamp or other light sourcehaving an integral collector 145 (see FIG. 16) that collects the lightfrom the light source and focuses the light. In either case the lightfrom the light source is preferably focused in a predetermined patternon the input surface 146 of the light transition area 6 which directsthe light at an acceptable angle for entering the light input edge 18 ofthe light emitting panel 7 over a substantial portion of the crosssectional area of the panel.

FIG. 44 schematically illustrates still another form of light emittingpanel assembly 150 in accordance with this invention which isparticularly adapted to be used for different types of phototherapytreatment by exposing various portions of the skin or eyes of a personto light being emitted from the panel assembly to treat such conditionsas neonatal hyperbilirubinemia, insomnia, sleep disorders or tirednessassociated with jet lag or shift work, certain types of psychiatricdisorders such as seasonal affective disorder (SAD) and depression andso on. To that end, the light emitting panel assembly 150 includes alight emitting panel member 151 which may be in the shape of a pad orblanket. At one or both ends of the panel member 151 are one or morelight transition areas 152 containing one or more LEDs or other lightsources 3 for uniformly supplying light of any desired wavelength to thepanel input edge 154 at one or both ends of the panel member. Ifdesired, the light sources may be different colored LEDs so that thelight from the LEDs can be mixed to produce virtually any desiredcolored light output distribution including white light from the panelmember. Also, white LEDs may be used for producing a white light outputdistribution from the panel member.

On one or more selected panel surface areas on one or both sides of thepanel member 151 are a pattern of light extracting deformities ordisruptions which are not shown in FIG. 44 but may be of any of thetypes previously described for producing a desired light outputdistribution from the panel surface areas. The portion of the body of aperson to receive phototherapy treatment may be placed in closeassociation with or directly against the light emitting surface areas ofthe panel. Alternatively, the panel assembly 150 may be provided withmolded portions 155 at strategic locations on the panel member 151 (forexample at all four corners) for providing structural support forlocating other parts or components such as a diffuser or lens 156 asschematically shown in FIG. 45.

FIG. 46 shows still another form of light emitting panel assembly 160 inaccordance with this invention for use in phototherapy treatment orother applications in which an array of LEDs or other light sources 3are mounted on a printed circuit board 162 for directing light through atransparent member 163 which may be a diffuser or lens. The transparentmember 163 is maintained in spaced apart relation from the printedcircuit board 162 and light sources 3 mounted thereon by a plurality ofupstanding supports 164 on a base 165 for the circuit board. Not onlydoes this protect the circuit board 162 and light sources 3 againstdamage, but also provides an air gap 166 between the light sources 3 andtransparent member 163 to facilitate dissipation of any heat that isproduced by the light sources.

In FIG. 46 the circuit board 162 and transparent member 163 are shown asbeing substantially flat. However, it will be appreciated that suchcircuit board 162 and transparent member 163 may also be curved asschematically shown in FIG. 47 for supporting a body part such as anarm, leg or neck of a person receiving phototherapy treatment.

The various light emitting panel assemblies disclosed herein may be usedfor a great many different applications including for example liquidcrystal display (LCD) or other signage back lighting or lighting ingeneral, decorative and display lighting, automotive lighting, dentallighting, phototherapy or other medical lighting, membrane switchlighting, and sporting goods and apparel lighting or the like. Also thepanel assemblies may be made such that the panel members and deformitiesare transparent without a back reflector. This allows the panelassemblies to be used for example to front light an LCD or other displaysuch that the display is viewed through the transparent panel members inthe manner previously described.

The pattern of the various optical deformities disclosed herein may alsobe varied in size, shape, density, placement, angle, rotation and/ortype on or in one or more surface areas of a light emitting panel memberto produce a desired light output distribution from the panel member tosuit a particular application. By varying the pattern of opticaldeformities, the light output distribution can be made to besubstantially uniform throughout all or a portion of the length of thepanel member or variable to increase or decrease the brightness of oneor more surface areas of the panel member.

Also, by varying the pattern of optical deformities, the light outputdistribution of the panel member can be made to have more complicatedfeatures. For example, FIGS. 48 and 49 show light emitting panelassemblies 170 of the present invention in which the light outputdistribution of a specific area or areas of the light emitting panelmembers 171 may be in the form or shape of text 172, graphics or logo173 and/or image 174 (hereafter individually or collectively referred toas a design/image 175). The dark and light areas shown in the lightemitting regions in FIGS. 48 and 49 (as well as those shown in FIGS.50–52) can be interpreted as either the higher light output areas or thelower light output areas. Also, the dark and light areas shown can haveeither a uniform light output from a given region, or a variable lightoutput throughout the region such as a multi-level output distributionused to create a picture in an output distribution, for example.Moreover, the dark and light regions may have abrupt boundaries or theboundaries may be blended together so that there are no distinctboundaries between regions as desired. Generally any of the dark andlight areas of FIGS. 48–52 may be interpreted in the above fashion.

The portions 176 of the design/image output distribution 175 that arerelatively dark may be formed by surrounding the outline of therelatively dark portions with a suitable pattern of the opticaldeformities, whereas the portions 177 of the design/image outputdistribution 175 that are relatively bright (e.g., light) are shaped byplacing a suitable pattern of the optical deformities in the shape ofsuch relatively bright portions. Any desired variations in or uniformityof the intensity of the light output distribution of any portion of thedesign/image 175 may be obtained by varying the size, shape, density,placement, angle, rotation and/or type of the optical deformities.

The panel members may be lighted from one or more ends or sides byoptically coupling one or more light sources to one or more input edgesof the panel member. Panel members 171 of FIGS. 48 and 49 are shownbeing lighted by two light sources 3 optically coupled to input edges180 and 181 adjacent each end of the panel members. However, it will beappreciated that any number and type of light sources may be used tolight the panel members depending on the particular application.

The optical deformities may also be shaped or oriented to extract lightpropagating through the panel members preferentially in one directionover another. This allows different sets of optical deformities to beused to extract light in different preferred directions to construct anydesired form or shape of design/image output distribution.

Different colored light sources may also be optically coupled todifferent input edges of the panel members so that the different sets ofoptical deformities will cause a preferred color of light to be emittedfrom the panel members. In this way, multi-colored output distributionscan be created to suit a particular application. For example, ifdifferent colored light sources are optically coupled to the input edges180 and 181 at opposite ends of the panel members 171, different sets ofoptical deformities may be shaped or oriented to extract lightpropagating through the panel members preferentially in one directionover another for causing the different colored light received by thedifferent input edges to create a design/image output distribution thatis multi-colored. In addition, by mixing the different sets of opticaldeformities within a given area, the light source colors may be mixed toproduce colors in the output distribution that are different from thelight source colors.

The size of the design/image output distribution in relation to anotherlight output distribution or distributions of the panel members may bevaried as desired depending on the particular application. For example,FIGS. 48 and 49 show a design/image output distribution 175 that isrelatively large in relation to another light output distribution 185 ofthe panel members, whereas FIG. 50 shows a design/image outputdistribution 175 that is relatively small in relation to another lightoutput distribution 185 of the panel member.

Making the design/image relatively small will permit the design/imageoutput distribution to be placed wherever desired in another outputdistribution of the panel member (which may, for example, be uniform) tocreate a watermark, logo, security marking, label or other effect in theother output distribution. For example, the panel member 171 of FIG. 50may be used to backlight a display 186 such as a liquid crystal displayof an optical assembly 190 as shown in FIG. 51. If the design/imageoutput distribution 175 of the panel member 171 is placed in a corner ofthe panel member as shown in FIG. 50, the design/image will be viewablein a corner of the display 186 as shown in FIG. 51 to create, forexample, a “corporate presence” on the display without obscuring imagesor other data being displayed on the display.

An optical assembly may also be comprised of multiple light emittingpanel members overlying one another, each having a different lightoutput distribution or color that produces one or more portions or partsof a more complicated light output distribution or an image with morethan one dimension. One such optical assembly 191 is schematically shownin FIG. 52, and includes two (or more) light emitting panel members 171,each having a different light output distribution 192, 193 that producesa portion of the total design/image output distribution 194 that can beseen when viewed through both panel members or through a display 195overlying the panel members. The term display as used herein mayinclude, for example, one or more liquid crystal displays, opticalfilms, diffusers, touch pads, and/or transparent or semi-transparentoverlays or covers and the like.

The intensity of the light output distribution of each of the panelmembers 171 may be different to create a multi-intensity composite lightoutput distribution when viewed through the panel members or thedisplay. Also, since each of the panel members may have its own lightsource or light sources 3, different colored light sources may be usedfor each panel member to produce a different colored light outputdistribution for each panel member which when viewed through both panelmembers or a display overlying the panel members will produce amulti-colored composite light output distribution 194.

One or more transparent brightness enhancement films, light managementfilms, diffuser films, color filters or other films 196 may also beattached or positioned in close proximity to the side or sides of thepanel members from which the emitted light is viewed to produce adesired effect. For example, the films 196 may be light redirectingfilms or light management films having optical deformities thatredistribute the light passing through the films such that thedistribution of light exiting the films is directed more normal to thesurface of the films. Also the films 196 may be color filters ordiffusers having for example prismatic or lenticular deformities on orin the films that allow different light output distributions to be seenwhen the panel members are viewed through the films (and the display)from different angles. Other optical deformities 197 such as prismaticor lenticular optical deformities may also be provided on the side ofthe panel member or members 171 opposite the side on which the patternof optical deformities is provided as further schematically shown inFIG. 52 to allow different light output distributions to be seen whenthe panel member or members are viewed through the other opticaldeformities from different angles.

Although the invention has been shown and described with respect tocertain preferred embodiments, it is obvious that equivalent alterationsand modifications will occur to others skilled in the art upon thereading and understanding of the specification. In particular, withregard to the various functions performed by the above-describedcomponents, the terms (including any reference to a “means”) used todescribe such components are intended to correspond, unless otherwiseindicated, to any component which performs the specified function of thedescribed component (e.g., that is functionally equivalent), even thoughnot structurally equivalent to the disclosed component which performsthe function of the invention. In addition, while a particular featureof the invention may have been disclosed with respect to only one ofseveral embodiments, such feature may be combined with one or more otherfeatures of the other embodiments as may be desired and advantageous forany given or particular application.

1. An optical assembly comprising a light emitting panel member havingopposite sides and at least one input edge for receiving light from atleast one light source, and a pattern of individual optical deformitieson or in at least one side of the panel member for producing a lightoutput distribution from a light emitting surface area of the panelmember, the individual optical deformities being varied throughout thepattern to cause the light output distribution to be generally uniformand provide a generally uniform field of illumination for a liquidcrystal display overlying the light emitting surface area except in alocalized region within the uniform field of illumination where theindividual optical deformities are varied to create a watermark,security marking, label or other effect within the uniform field ofillumination having a form or shape of at least one of text, graphics,logo or image that is viewable through the display, each element of thetext, graphics, logo or image being comprised of a plurality of theindividual optical deformities which are quite small in relation to thelength and width of each element of the text, graphics, logo or imageformed thereby.
 2. The assembly of claim 1 wherein the light source is acolored light source.
 3. The assembly of claim 1 wherein the panelmember has at least two input edges at different end edges or side edgesof the panel member for receiving light from at least two differentlight sources.
 4. The assembly of claim 3 wherein the different lightsources are different colored light sources.
 5. The assembly of claim 4wherein the different colored light sources are different colored lightemitting diodes.
 6. The assembly of claim 4 wherein the differentcolored light sources are flashed to produce a desired colored lightoutput distribution.
 7. The assembly of claim 1 wherein the opticaldeformities of the one pattern are varied to obtain a multi-intensitylight output distribution.
 8. The assembly of claim 1 further comprisingat least one other light emitting panel member having a different lightoutput distribution than the one panel member, the panel members beingin overlying relation to one another for producing at least onecomposite light output distribution when viewed through the panelmembers from one side.
 9. The assembly of claim 8 wherein the otherpanel member has at least one light output distribution in the form orshape of at least one of text, graphics, logo or image.
 10. The assemblyof claim 8 wherein each of the panel members receives light from atleast one different colored light source to produce at least onemulti-colored composite light output distribution when viewed throughthe panel members from the one side.
 11. The assembly of claim 8 whereinthe light output distribution of each of the panel members produces oneor more parts of a more complex light output distribution that isvisible through the panel members from the one side.
 12. The assembly ofclaim 8 wherein the intensity of the light output distribution from eachof the panel members is different and creates at least onemulti-intensity composite light output distribution that is visiblethrough the panel members from the one side.
 13. The assembly of claim 8further comprising a display overlying the one side of the overlyingpanel members, the light output distributions of the overlying panelmembers being visible through the display.
 14. The assembly of claim 13further comprising at least one light redirecting film between thedisplay and at least one of the panel members.
 15. The assembly of claim1 wherein at least some of the optical deformities are prismatic orlenticular optical deformities.
 16. The assembly of claim 1 wherein thepanel member has at least two input edges at different end edges or sideedges of the panel member for receiving light from at least twodifferent light sources.
 17. The assembly of claim 16 wherein the inputedges receive light from different colored light sources, and at leastsome of the optical deformities in the one pattern are shaped ororiented preferentially to cause the different colored light received bythe different input edges to create at least one multi-colored lightoutput distribution.
 18. The assembly of claim 1 further comprisingadditional optical deformities on or in the opposite side of the panelmember for generally emitting light in a different direction, such thatdifferent light output distributions are seen when the panel member isviewed from different angles through a side.
 19. The assembly of claim 1further comprising at least one light redirecting film in closeproximity to the panel member that allows different light outputdistributions to be seen when the panel member is viewed through thefilm from different angles.
 20. The assembly of claim 19 wherein thefilm is a prismatic or lenticular brightness enhancing film or lightmanagement film.
 21. An optical assembly comprising a light emittingpanel member having opposite sides, at least one input edge forreceiving light from at least one light source, and at least one patternof individual optical deformities on or in at least one side of thepanel member for producing a light output distribution from a lightemitting surface area of the panel member, the individual opticaldeformities being varied throughout the pattern to cause the lightoutput distribution to be generally uniform and provide a generallyuniform field of illumination for a liquid crystal display overlying thelight emitting surface area except in a localized region within theuniform field of illumination where the individual optical deformitiesare varied to create a watermark, security marking, label or othereffect within the uniform field of illumination having a form or shapeof at least one of text, graphics, logo or image that is viewablethrough the display, each element of the text, graphics, logo or imagebeing comprised of a plurality of the individual optical deformitieswhich have at least one well defined sloping surface and a length andwidth that are quite small in relation to the length and width of eachelement of the text, graphics, logo or image formed thereby.